Hi Vandhana, You can go to Southeast Asian countries as they have a fast visa procedure and many of them have visa-on-arrival and they are generally easy on wallet. You can go to Thailand as the tourist sector is very developed there and it is a great place for solo backpackers to start and it has visa-on-arrival for Indians for the period of 14 days. You can explore amazing trips to Thailand by Tripoto wanderers here: https://goo.gl/gnHWuJ Keep exploring!
Vandhana only thailand ( avoid cliche phuket instead include Koh Samui ) and cambodia will be the best choice for a budget of 40 k for solo trp and also recall if your budget is 40k you should still keep min 20k handy with you, provided emergency if you miss a flight or your cards don't work. And dont use credit cards on your trip, will levy huge surcharge, always use debit card and keep some local currency available in hand at all times. Happy Backpacking :)